Brake mechanism



Jan. 17, 1939- R. H. Rosi-:NBERG 2,143,998

BRA-KE MECHANISM Filed Aug. l7 1937 2 Sheets-Sheet l INVENTOR ORNEYS Jan. 17, 1939. R H, RSENBERG 2,143,998

BRAKE MECHANISM Filed Aug. 17, 193'?` 2 Sheets-Sheei 2 ma i f5 /'jfi il mi f2 INK/f@ f ATTORNEYS IIN' Patented Jan. 17, 1939.

lUNITED STATES BRAKE MECHANISM Ralph H. Rosenberg, Detroit, Mich., assignor, by

direct and mesne assignments, to Detroit Duo- Grip Brake Corporation, a. corporation of Michigan Application August 17,'1937, serial No. 159,511

1o claims. (o1. 13s- 76) 1 This invention relates broadly to brakes for motor vehicles and more specifically to' improvements in the brake shoe actuating mechanism and the supporting linkage thereforz One of the objects of the invention is to provide a brake shoe actuating mechanism having an adjustment therein for the equilization of brake shoe pressure upon the brake drum.

Another object of the invention is to provide an internal and external shoe actuating mechanism which is constructed to eiect the simultaneous and uniform mvement ofthe shoes, and to avoid the imposition of undue strain and the consequent deection during the operation of the brake.

Another object of the invention is to provide a brake shoe supporting structure which is adapted to maintain the loads imposed upon the respective shoes in balanced relation,

Another object of the invention is to provide a brake operating mechanism which is constructed to facilitate the ready adjustmentof parts thereof which is durable of structure and economic of manufacture.

Other objects and advantages more or less ancillary of the foregoing and the manner in which all the various objects are realized will appear in the following description which, considered in connection with the accompanying drawings, sets forth the preferred embodiment lof the invention.

Referring to the drawings in which the embodiment of ,the invention is illustrated as applied upon a propeller shaft of a motor vehicle.

Fig. 1 is a front elevational view of a propeller shaft and brake drum of an automobile and the brake mechanism embodying the present invention;

Fig. 2 is a side elevational view of the brake mechanism illustrated in Fig. 1 including a fragmentary portion of an automobile transmission housing; I

- Fig. 3 is a sectional View of a fragmentary portion of the brake drum assembly and the brake operating mechanism embodying the present invention, the section being taken on a plane indicated by the line 3--3 in Fig. 1;

Fig. 4 is an inverted plan view of the external brake shoe, including certain component parts of the brake linkage assembly; and

Fig. 5 is a diagrammatic view of the brake drum and brake actuating mechanism illustrating the disposition and angular relation of the brake shoe supporting forks and the actuated position of the forks.

Referring first to Fig. 2 the brake drum lII) is .bolted to the iianged portion of a sleeve II mounted upon the splined end of a drive shaft I2 extending from the transmission housing I3. Upon the rearward face of the transmission housing there is an arm I4 having a pintle I5 in the outer end thereof for the support of the brake shoes and actuating mechanism therefor; The anchor post or pintle I5 is disposed in paiallel relation to the outer face of the flange of the brake drum I 0 and is of a length substantially equal to the width of the flange. 'The free end of the pintle is threaded for the reception of `a nut which is provided for' the retention of a pair of links I6 pivotally mounted upon the pintle and held in spaced relation thereon by a sleeve I1. The external brake shoe I8 is suspended from the links I6 by a pin I9 pivotally mounted in a boss 2li in the outer face of the brake shoe adjacent the end thereof. The opposed end of the brake shoe I8 is supported by a pin 2| mounted for pivotal movement in a boss 22 formed in the en d portion of the shoe. The internal brake shoe 23 is similarly supported by pins 24 and`25 fulcrumed in bosses 26 in the end portions of the shoe. The outer ends of the pins I9 and 24 are secured in an arm 21 which, together with the pins comprise a fork assembly 28 fulcrumed upon the pin I9 and movable in the path dened by the oscillation of the links I6. The pins 2I and 25 supporting the opposed ends of the brake shoes I8 and 23 are secured in an arm 29, the pin and arm assembly comprising a fork 30 which is fulcrmed upon the pin 2I for movement radially towards and eircumferentially about the `brake drum IIJ upon actuation of the brake operating lever 3l. The arms 21 and 29 are formed with split bosses in the outer ends thereof which are machined to retain Vdraw bolts and nuts 32 for clamping the eccentric head portion 33 of the pin I9. The eccentrics 33 are provided to facilitate adjustment of the brake shoes, compensative of wear of the brake lining 34, and to facilitate independent adjustment of each end of each shoe relative the periphery of the brake drum. The brake actuating lever or arm 3I is preferably constructed with a threaded shank adapted for assembly Within the bore of the split boss in the arm 29. The lever 3l is disposed in angular relation to the arm 29, the assembly comprising the pins, arm and lever constituting a bell crank which is. fulcrumed upon the pin 2I in the outer end of the external brake shoe I8. Upon the end of the lever 3| there is a shackle 35 pivotally connected to a link 36 and coupled through a second shackle 2 v 39 secured to the transmission housing 3. The upper arm of the bell crank 38 is pivotally connected to a rod 40 which is connected to the brake actuating lever, not shown, in the customary manner.

'I'he inner brake shoe 23 is formed so that the area of the brake drum engaging surface is equal to that of the external brake shoe` |8, the upper or leading edge of the internal brake shoe being disposed circumferentially forward of the end portion of the external shoe. The forks 28 and 30 are preferably formed from forgings having the pins for the internal brake shoes assembled,

in the arms and retained therein by pins or keys 4|.

The brake shoes are formed with ribs 42 extended throughout their length and provided to prevent deflection of the end portions thereof. The supporting pin bosses 20, 2| and 25 and 26 are disposed in spaced relation with the ends of the respective brakes in order to accommodate the assembly of rivets for the securement of the brake lining 34 upon the face of the shoes.

As illustrated diagrammatically in Fig. 5 when the pull rod 4D is actuated in the direction of the arrow, the brake operating lever 3| is elevated to the position indicated in dotted lines, while the external brake shoe and pin 2| are moved circumferentially about and towards the brake drum. The movement of the pin 2| causes the bell crank assembly to be rocked upon its fulcrum and effects the translation of the internal brake shoe towards the fork 28 and also towards the inner periphery of the drum I0. the pin 24 thefork 28 is twisted or rocked upon its fulcrum I9, thus causing the links I6 to swing inwardly and carry the pin I9 towards the brake drum. As illustrated by the dotted line position of the forks the distance between the pins and periphery of the brake drum is foreshortened upon actuation of the lever 3| and the resultant oscillation of the forks 30 and 28 upon their fulcrums. Since-the internal brake shoe is supported by the forks or linked connection to the external brake shoe it will be readily recognized that the movement of the two shoes will be uniform and equal and that adjustment of the arm 3| will cause the shoes to impinge the flange of the brake drum IIJ.

It will be noted that the movement ofthe external brake shoe is restricted at itsfupper end by the pendulous movement of the links |6 but that the `opposed end of the external brake shoe is advanced circumferentially about the drum and radially inward when the bell crank assembly of the fork 30 is twisted upon its fulcrum bearing in the end of the external brake shoe. Likewise the circumferential movement of the upper end of the internal shoe is less than that of the opposed end thereof. However, as is apparent in Fig. 1 and Fig. 5 the inner end of the arm 29 is inclined toward the periphery of the drum more than the inner end of the arm 21, thus though the pin 25 moves through a greater arc'than the pin 24, the angle of movement thereof towards the brake drum flange is sharper than the angular movement of the pin 24, hence the timed relation of movement of the two pins, as provided herein, is so equalized as to effect uniform engagement of the full area of the shoes with the brake drum and the simultaneous equi-distant movement of two shoes toward and away from the drum. The web of the brake drum l0 is preferably provided with a-plurality of holes 43 drilled at an angle Upon actuation' of which will induce the circulation of air into the drum and over the internal brake shoe member.

Although the foregoing description is necessarily of a vdetailed character, in order' that the invention may be completely set forth, it is to be understood that the specific terminology is not intended to be restrictive or confining, and that Various rearrangements of parts andmodications of detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim:

1. A brake mechanism comprising a brake drum, an internal and external brake shoe coordinated therewith, an anchor post, a fork member pendulously mounted thereon and mounted for oscillatory movement relative thereto, an end of said internal and external brake shoes being pivotally supported upon said fork, a second fork pivotally -connected with the opposed ends of said brake shoes, and means for oscillating one of said forks.

2. A brake mechanism comprising a brake drum, an internal and external brake shoe coordinated therewith, a. xed anchor post, a link pivotally mounted thereon, a vfork pivotally mounted on said link, an end of the internal and external brake shoe being pivotally mounted on said fork, a secondv fork pivotally connected with the opposed ends of said shoes, and a lever on one of said forks adjacent one of the pivotal connections for oscillating the fork. y

3. A brake mechanism comprising a brake drum, an internal and external brake shoe coordinated therewith, a fixed anchor post, links pivotally mounted thereon, a fork comprising an arm and a pair of pins, one of said pins being" pivotally'mounted in said links and in one of said brake shoes, the other of said pins being pivotally mounted in the other brake shoe,a second fork comprising an arm and a pair of pins,

each pivotally mounted in one of said brake shoes, and a lever on the last named fork disposed in relation to one of the pins so that the arm of the 'fork will fulcrum thereon as said lever is actuated.

4. A brake mechanism comprising a brake drum, an internal and external brake shoefcoordinated therewith, a fixed anchor post, links pivotally mounted thereon, a fork comprising an arm and a pair of pins, one of said pins being pivotally mounted in said links and in one end of the external brake shoe, the other of said pins being pivotally mounted in the adjacent end of the internal brake shoe, a second fork comprising an arm and a pair of pins, each pivotally'mounted in the opposed ends of the brake shoes and a brake operating lever affixed upon said last named fork adjacent the pin'in the external brake shoe.

5. A brake mechanism comprising a brake drum, an internal and external brake shoe coordinated therewith, a/ixed anchor post, links pivotally mounted thereon, a fork comprising an arm and a pair of pins, one of said pins being pivotally mounted in said links and in one end of the external brake shoe, the other of said pins being pivot-v ally mounted in the adjacent end of the internal brake shoe, a second fork comprising an arm and a pair of pins, each pivotally mounted in the opposed ends of the brake shoes, the arm of said second named fork being inclined so that the pins of the fork are closer to the periphery of the brake drum than the pins of the first named fork, and an operating arm upon the second named fork adjacent the external brake shoe supporting pin.

6. A propeller shaft brake for a motor vehicle, comprising a brake drum, a pair of brake shoes of equal brake engaging area, disposed respectively adjacent the inner and outer face of the flange of said brake drum, an anchor post, a link pivoted thereon, a fork pivoted thereto and to the outer brake, said fork uniting through pivotal connections said inner and outer brake shoes, a second fork uniting through pivotal connections the opposed ends of said shoes and a control lever affixed to the last named fork and constituting therewith a bell crank fulcrumed upon the pivotal connection of the fork with the outer brake shoe.

'7. In a motor vehicle having a transmission case and a propeller shaft, a .brake mechanism comprising, a anged brake drum mounted on said propeller shaft, an internal and external brake shoe adjacent the flanged portion of said drum, an arm affixed to said transmission case, an

anchor post therein, links pivotally mounted on said anchor post, apin pivotally mounted in said link and the end of said external brake shoe, an

arm affixed to said pin, a second pin affixed to said I arm and pivotally connected to the end of the internal brake shoe, a pin in the opposed end of said external brake shoe, an arm affixed thereto, a second pin aixed to said arm and pivotally connected to the internal brake shoe and a brake operating lever affixed to said arm adjacent the pin in the external brake shoe.

8. A brake mechanism comprising, a brake drum, an internal and external brake shoe coordinated therewith, an anchor post, a link pivoted thereon, a pin having an eccentric head pivotally connected to said link and an endof said Yexternal brake shoe, an arm clamped to the eccentric head of said pin, a second pin aixed in said arm and' pivotally connected to the end of said internal brake shoe, a pin having an eccentric head pivotally mounted in the opposed end of said external brake shoe, a second arm clamped to the eccentric head of the` last named pin, a pin ail'ixed in the second named arm and pivotally connected to said internal brake shoe, and a brake operating le 'er on said lastnamed arm and extended laterally from a point adjacent the pin in the external brake shoe. i i

9. A brake mechanism comprising, a brake drum, an internal and, external brake shoe coordinated therewith, an anchor post, a link pivoted thereon, a pin pivoted to said link and one end of said external brake shoe, an arm connected to said pin, a second pin secured in said arm and pivoted in one end of said internal brake shoe, a pin in the opposed end of the external brake shoe, an arm connected to said pin, a second pin secured in said arm and pivoted in the opposed end of said internal brake shoe, a brake operating lever mounted on the last named arm adjacent one of the pins therein and means for adjusting the pins in the respective ends of the internal and external brake shoes towards and away from each other.

10. A brake mechanism comprising, a brake drum, an internal and external brake shoe coordinated therewith, an anchor post, a link pivoted thereon, a pin pivoted to said link and one end of said external brake shoe, an arm connected to said pin, a second pin secured in said arm and pivoted in an end of said internal brake shoe, a pin in the opposed end of the external brake shoe, an arm connected to said pin, a second pin secured in said arm and pivoted in the opposed end of said internal brake shoe, a brake operating lever mounted on the last named arm adjacent one of thepins therein, said last named arm being disposed at a more acute angle, relative to a brake drum radius through the external brake shoe pin, than the angle of the first named arm, relative to a brake drum radius through the external brake shoe pin thereof, and adjustable eccentrics in the external brake shoe pins for drawing the respective ends of the internal and external brake shoes towards or away fromy each other.

' RALPH H. ROSENBERG. 

